| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 6141246 | Virology | 2012 | 11 Pages |
Regulation of NIa-Pro is crucial for polyprotein processing and hence, for successful infection of potyviruses. We have examined two novel mechanisms that could regulate NIa-Pro activity. Firstly, the influence of VPg domain on the proteolytic activity of NIa-Pro was investigated. It was shown that the turnover number of the protease increases when these two domains interact (cis: two-fold; trans: seven-fold) with each other. Secondly, the protease activity of NIa-Pro could also be modulated by phosphorylation at Ser129. A mutation of this residue either to aspartate (phosphorylation-mimic) or alanine (phosphorylation-deficient) drastically reduces the protease activity. Based on these observations and molecular modeling studies, we propose that interaction with VPg as well as phosphorylation of Ser129 could relay a signal through Trp143 present at the protein surface to the active site pocket by subtle conformational changes, thus modulating protease activity of NIa-Pro.
⺠NIa-Pro protease activity enhanced by interaction with VPg. ⺠Trp143 in NIa-Pro is present at the face interacting with VPg. ⺠NIa-Pro can be phosphorylated at Ser129 by plant cellular kinases. ⺠Phosphorylation at Ser129 causes Cys151 flip and drastically reduces activity. ⺠Surface to active site signal relayed by a network of interactions in “W-C region”.
